Apparatuses for detecting the edge of a material web using a plurality of ultrasound sensors are known, as shown in U.S. Pat. No. 7,357,027 B2, for example. In order to provide a certain measurement range, these apparatuses have a multiplicity of individual ultrasound sensors arranged in an array, with each individual ultrasound sensor comprising an ultrasound transmitter element and an ultrasound receiver element. In this arrangement, each ultrasound receiver element has a dedicated associated ultrasound transmitter element which applies an ultrasound signal to said ultrasound receiver element. Such apparatuses require a large number of transmitter and ultrasound receiver elements, which increases the complexity and costs of the apparatus.